Hangzhou Qiwei Instrument Co., Ltd. is one of the leading manufacturers and suppliers of benchtop cod analyzer in China. With a professional production team, we are able to meet the needs of the majority of our customers. Welcome to wholesale bulk benchtop cod analyzer in stock here from our factory. We also accept customized orders.
product key technologies
Benchtop COD Analyzer is designed for rapid measurement of Chemical Oxygen Demand (COD). COD represents the amount of oxidant consumed by a strong oxidant under standard test conditions. This parameter indicates the total reducing substances in a water sample, where organic matter is the main component, together with nitrites, sulfides, and ferrous salts. A higher COD reading means more severe organic pollution in that water body.
The analyzer uses a composite catalyst in its reagent formulation. This catalyst accelerates oxidation and reduces chloride ion interference. After the digestion device completes a fast redox reaction between the sample and the reagent, trivalent chromium ions (Cr³⁺) are produced. The instrument then determines the Cr³⁺ concentration by spectrophotometry and calculates the corresponding COD value.
Stability, accuracy, measuring range, and user convenience have been improved in this device. It meets different testing needs across various scenarios. Common applications include monitoring industrial wastewater from chemical, petroleum, coking, paper, metallurgical, brewing, and pharmaceutical industries, as well as analyzing municipal sewage, domestic wastewater, and surface water from rivers and lakes.
Performance Indicator
|
Model |
QW-COD-T |
|
Ambient Temperature |
5 - 40℃ |
|
Relative Humidity |
< 85% (no condensation) |
|
Power Supply |
AC 220V±10% / 50Hz |
Technical Parameter
|
Model |
QW-COD-T |
|
Method Of Determination |
Rapid catalytic method (chromium method) |
|
Measuring Range |
0~150 mg/L low range; 100~1000 mg/L high range (diluted measurement is required when the concentration is above 1000 mg/L) |
|
Measuring Error |
5~100 mg/L, absolute error ≤ ±5 mg/L; 100~1000 mg/L, relative error ≤ ±5% |
|
Dissolution Temperature |
165 ± 1℃ |
|
Dissolution Time |
20 minutes |
|
DeterminationTime |
20 minutes. Can be used to measure 9 wells or 25 wells simultaneously (depending on the configuration of the digestion instrument) |
|
Temperature Indication Error |
<±1℃ |
|
Temperature Field Uniformity |
≤ 2℃ |
|
Indication Error |
≤ ±2% |
|
Record Storage |
It can store 20 measurement results |
FAQ
Q: What factors will affect the test results of the portable rapid COD analyzer?
A: The determination of COD is affected by numerous factors, including the type and concentration of oxidant, sample homogeneity, acidity of the reaction solution, reaction temperature and duration, and the addition of catalysts. Among these factors, sample homogeneity plays a vital role.Insoluble suspended particles and flocs in general industrial wastewater tend to settle down or cause liquid stratification, resulting in inconsistent solute concentrations across the water body. The standing time of field samples also exerts an impact on test results: the longer the sample is left standing, the more severe the sedimentation of solutes becomes. In addition, sampling position and depth will also lead to divergent test readings. For instance, there is a notable deviation between the COD values tested directly at the drain outlet on site and those measured in the laboratory with water sampled from the same outlet. Likewise, samples taken from deep water and shallow water will yield different results.Flow monitoring delivers real-time COD concentration of water quality and supports on-line continuous detection. By contrast, laboratory testing only measures the COD concentration of collected samples and cannot reflect real-time water quality conditions.Different pre-treatment methods for samples, such as static sedimentation duration and filtration, will also cause discrepancies in test results. The filter screen shall be cleaned timely once clogged; otherwise, the filtration efficiency will be compromised and the instrument readings will be inaccurate.The oxidation of chloride ions in wastewater will cause the readings of portable rapid COD analyzers to be higher than the actual values. Moreover, the application of different reagents such as mercuric sulfateor silver nitrate to remove chloride ions will also affect the final test results.
Q: Why does the temperature alarm or error message pop up during digestion?
A: Many bench-top COD detectors are equipped with a digestion module. If the screen shows abnormal temperature alerts or error codes starting with "Err", the issue generally lies with the heating system.
First, power off and restart the device, then reset the digestion temperature program and run it again. If the alarm persists, check for foreign objects or spilled liquid inside the digestion wells which may cause short circuits, and clean the area with a dry cloth.
Poor heat dissipation due to a non-functional cooling fan will also trigger overheat protection. Please check whether the fan is clogged with dust.
If none of the above solutions work, the heating element or temperature sensor is most likely damaged, and the equipment needs to be sent back to the factory for repair.
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